Syndiotactic polystyrene aerogels containing multi-walled carbon nanotubes

This work investigated the effects of multi-walled carbon nanotubes (MWCNTs) on density, surface area, compressive strength, and electrical conductivity of syndiotactic polystyrene (sPS) aerogels. The non-covalently modified MWCNTs were dispersed in sPS solution before thermo-reversible gelation of the polymer. The aerogels were obtained by exchanging the solvent with liquid carbon dioxide and by removing carbon dioxide under supercritical condition. The materials were characterized by electron microscopy, wide angle X-ray diffraction, differential scanning calorimetry, and nitrogen adsorption and desorption isotherms. It was found that sPS phase formed strands of approximately 50 nm in diameter and that MWCNTs formed an interpenetrating network within the sPS aerogel. The presence of MWCNTs caused little changes in morphology, crystalline structure of sPS, and surface areas of the aerogels, but significantly increased the compressive modulus and electrical conductivity. The electrical conductivity also showed sensitivity to compressive strain.